Article sorting system



P 13, 1956 K. T. WILDER ARTICLE SORTING SYSTEM 5 Sheets-Sheet 1 FiledJan. 2, 1964 FIG.|

46 33d. n w a In 46-] INVENTOR. KARL T. WILDER ATTORNEY p 1966 K. "r.WILDER ARTICLE SORTING SYSTEM 5 Sheets-Sheet 2 Filed Jan. 2, 1964 soiwu/soN PIC-3.5

I 5 L L 535 3 FIG.6

45 (STEP DOWN] r' 50(5TEP oowm FIG.7

INVENTOR. KARL. T. WILDE R BY (NF ATTORNEY United States Patent3,272,353 ARTICLE SORTING SYSTEM Karl T. Wilder, Randolph Township,N.J., assignor t0 ECD Industries, Mountainside, N.J., a partnershipFiled Jan. 2, 1964, Ser. No. 335,172 24 Claims. (Cl. 214-11) Thisinvention relates to article sorting systems.

More particularly, it relates to such systems of the type where articlesare conveyed to successive discharge stations and are respectivelydischarged at selected stations.

In one such type of prior art system, the articles themselves, or theirrelated holders, carryusually in coded formthe address of their intendeddischarge station. An automatic reader at each station reads the addressinformation of each article and is effective to initiate discharge atthat station of any article whose address corresponds to the station.

Another type of prior art system involves a separate coded informationstrip carrying the article addresses. The strip is moved in synchronismwith the movement of the articles. The strip is sensed by respectivereading devices provided for each discharge station. When the addressinformation corresponds to the intended station, the reading meansinitiates discharge of the article at that station.

The foregoing types of systems are complex and therefore costly to buildand expensive to maintain. Both require a separate automatic informationreader for each discharge station. Further, the second typehaving thesynchronous information strip-necessitates the provision of means forencoding on the strip the address of each article entering the system.

The system of the present invention is a different and simpler type.Selection means is provided for selection of a discharge station for anyarticle. Operation of the selection means uniquely conditions controlcircuitry. As the articles move through the system in the same sequencein which the selections were made, the fact of article movement pasteach station will 'be detected, and the articles will be automaticallydischarged at their intended stations. There is no synchronism involvedas in the information strip system, nor are automatic readers needed.

Furthermore, despite its simplicity the present system permits the samedischarge station to be selected for different articles even though thefirst article selected for that station has not yet reached it. It isonly necessary that the articles move through the system in the samesequence in which the selections are made.

It is therefore a major object of the present invention to provide anovel article sorting system.

It is a further object to provide such a system which is relativelyinexpensive to construct and maintain.

It is a further object to provide such a system which, while simplerthan prior art systems, nevertheless has comparable desired selectionflexibility.

It is a more specific object to provide such a system wherein the samedischarge station can be selected a number of times even before thefirst article intended for that station has not yet reached it.

It is a further object to provide novel control circuitry for achievingthe preceding objects.

The above and other objects, features, and advantages of the inventionwill be apparent to those skilled in the art from the following detaileddescription when read in conjunction With the accompanying drawings, inwhich:

FIG. 1 is a schematic top plan view of one form of the novel sortingsystem of the invention.

FIG. la is a detail view of a station selecting button and the contactsit controls.

FIG. 2 is a diagram of the interlock circuit.

3,272,353 Patented Sept. 13, 1966 FIG. 3 is a diagram of the stackingrelay circuit.

FIG. 4 is a circuit diagram showing a portion of the control circuitry,and particularly how a stepping switch for each discharge station isoperated and controls the corresponding respective stepping switches forpreceding stations.

FIG. 5 is a diagram showing certain control circuitry for the stackingstepping switches for any one discharge station.

FIG. 6 is a circuit diagram showing the interconnection of the variousstepping switches for any one discharge station.

FIG. 7 is a diagram of the circuit means for any one station whereby themovement of an article to that station causes its stepping switches tostep back.

FIG. 8 is a diagram of other portions of the control circuitry of theinvention.

FIG. 9 is a schematic top plan view of a second form of the system ofthe invention, provided with plural loading points and plural selectioncontrol panels; and

FIG. 10 is a circuit diagram of the system of FIG. 9, for any onedischarge station.

Referring now to FIG. 1, the reference characters 1, 2, n, designate anumber of unloading or discharge stations disposed along the path ofmovement of a conveyor belt 10 on which are carried the articles 11 tobe selectively unloaded at these various stations. The details of theconveyor itself and its drive form no part of the present invention, andmay be of any suitable construction.

As seen in the top plan view of FIG. 1, the conveyor belt 10 is drivenfrom left to right. The articles 11 thereon are first carried past aselecting station 12 (or can be placed on the belt at the station 12) atwhich is provided a control panel 13 having a number of selector pushbuttons 14 each corresponding to a different related one of thedischarge stations 1, 2, n. The operator at the selecting station 12decides at which discharge station the article is to be unloaded, anddepresses the corresponding button 14. The particular characteristic orparameter of article 11 upon which the selection is based is immaterialso far as the present invention is concerned.

As will be described in detail shortly, the depression of the selectorbutton 14 uniquely conditions the control circuitry of the presentinvention. As the article 11 is carried toward the right past theselector station 12, it first traverses a light beam projected by lamp15 onto a starting photocell 16. Until the article passes the startphotocell 16, the selector buttons 14 will be ineffective for a furtherdischarge selecting operation.

Each discharge station includes a discharge arm or lever 20 which isnormally held in the ineffective position of FIG. 1 out of the path ofthe moving articles. Just upstream of its discharge arm, each dischargestation includes a related photocell 21 on which is projected a beam oflight by a lamp 22. As each article 11 is carried along toward the rightby belt 10, it successively blocks the beam of light falling on eachphotocell 21. Each such photocell-passing movement of the article 11causes a change in the condition of the discharge control means of theinvention.

As soon as article 11 passes the photocell 21 of the particular stationwhich has been selected for that articles discharge (by previousdepression of one of buttons 14), an operating solenoid 23 at thatstation will swing the discharge arm 20 clockwise so that the arm nowlies in the path of movement of the article. The operated position ofone of arms 20 is shown in broken lines in FIG. 1. Accordingly, as thefeed belt 10 continues its rightward movement, the article 11 will bediverted onto 3 a lateral discharge chute 24 or other suitable receivingstructure.

Extension 23a of the armature of each solenoid 23 operates discharge arm20 through an intermediate link 25. The latter is fixed to a rotatableshaft 26, as is arm 20. A tension spring 27 biases the just-describedmechanism to its normal, unoperated position.

As was mentioned earlier, one feature of the invention resides in thefact that the same discharge station can be selected for severaldifferent articles being carried along by the conveyor belt. Forexample, FIG. 1 shows three articles 11 on belt 10. With the presentsystem, station 2 can be selected for discharge of the rightmostarticle, station 1 for the next trailing article, and station 2 againcan be selected for the leftmost article, even before the leading(rightmost) article 11 has been discharged at station 2. The nature ofthe present invention is such that the same discharge station can beselected for various articles moving down the belt as many times asdesired either before or after the first of such articles has evenreached the discharge gate. Furthermore, such selection need not evennecessarily be of articles traveling in immediate consecutive order onbelt 10. This stacking capacity of the system is theoreticallyunlimited. In the actual design of a given system, it is achieved byrepeating certain control circuitry, shortly to be described, thedesired number of times.

Electric control circuitry The control circuitry of the invention willnow be described.

At this juncture, it may be mentioned that each station selecting button14 controls a number of electrical contacts 30, 41, 46. As shown in FIG.10, when any button 14 is operated to select a discharge station, itwill close these three contacts.

Contact 30 is effective to operate an interlock circuit. This circuitwill prevent all of the selector buttons 14 from being effective fordischarge selection until the article 11 for which a selection haspreviously been made by operation of a button 14, passes the startphotocell 16. This will prevent possible errors which could arise if abutton 14 were operated with no corresponding article placed or presenton belt 10, and another button 14 then depressed.

Interlock circuit Referring to FIG. 2, the interlock contacts 30 of allthe selector buttons 14 are connected in parallel with each other and inseries with a relay 31. (The numeral 30 is employed to designategenerally the interlock contact for any discharge selector button 14.However, the same numeral followed by a dashed number specificallydesignates the contact for the discharge station corresponding to thedashed number. For example, 30-1 refers to the interlock contactassociated with the first discharge station, etc. Similar nomenclaturewill be employed in connection with other parts.)

Operation of any one of the contacts 30, by depression of a relatedbutton 14, will energize relay 31 which will immediately lock in throughits normally open contact 31a, and a normally closed contact 32a of arelay 32. When the article 11 for which a gate selection has just beenmade passes the start photocell 16, cutting off its light beam, thephotocellwhich is in parallel with relay 32will rise in resistance inusual fashion, whereby relay 32 will operate. When relay 32 operates,its normally closed contact 32a will open, deenergizing relay 31. Untilrelay 31 is deenergized, its normally closed contact 31b (FIG. 3), tothe stacking relays 40 (whose function will be described shortly) willbe open, preventing the stack-, ing relays from operating in response todepression of a selector button 14.

A relay 33 (FIG. 2) is energized through normally open contact 310 ofrelay 31 so long as the latter is on. Normally closed contacts 33a (FIG.4) of relay 33 accordingly prevent operation of stepping switches 45,with which they are in series, until relay 31 opens, and thereby causesrelay 33 to open. As described later, stepping switches 45 are set inresponse to operation of the discharge selector buttons 14, and controldischarge of the article at the appropriate station.

If desired, an additional, normally open contact 31d (FIG. 2) of relay31 may be provided in series with a signal light or bell 34. Signal 34will be on whenever relay 31 is in energized condition. This willindicate to the operator that a discharge selection cannot be made againuntil the signal light goes oif.

Stacking control As was briefly mentioned earlier, the present systemprovides that the operator can select the same discharge station as theexit point for several articles 11 being carried by the feed belt 10,even though the first of the articles intended to discharge at thatstation has not reached it by the time the operator again selects it forsubsequent articles. For this purpose, there are provided for eachdischarge station a number of stacking relays 40 (FIG. 3). The number ofstacking relays at each station is equal to the maximum number ofarticles 11 to be selected for discharge at that station, prior to thetime the first of the articles intended for that station is dischargedthere. Stated difierently, there are as many stacking relays at astation as the desired maximum capacity to select that station todischarge articles coming toward it.

The stacking circuitry is arranged and operates as follows. Eachdischarge selector button 14, when operated, closes its associatedcontact 41 (FIGS. 1a, 3). Contact 41 is in series with theabove-mentioned interlock contact 31b of relay 31, and is thenceconnected in series with the various stacking relays 40I, 40H 40N, forthat discharge station through isolation diodes 42. (N, of course,represents the stacking capacity of the station.) Furthermore, anormally open contact of each stacking relay connected between all thenext successive stacking relays 40 of that station and the contact 41.Thus, there will be no such contact for the first relay 401; there is acontact 40I-II of relay 401 in series with relay 40II; the thirdstacking relay (if any) will have in series with it normally opencontacts of the second and first relays; the fourth stacking relay (ifany) will have in series with it normally open contacts of the third,second, and first relays; and so on.

From the foregoing it will be seen that operation of any given stationselector button 14 and consequent closure of its contact 41 willenergize the first stacking relay 40I, assuming of course that theaforedescribed interlock relay 31 is deenergized whereby its contact 31bis in its normal, closed condition. Operation of relay 40I will cause itto latch in through its normally open contact 40Ia and a normally closedcontact 62a of a related relay 62 (FIG. 8). Operation of relay 40I willalso cause closure of its normally open contact 40I-II in the primaryenergizing circuit (through contact 41) for the next stacking relay 40IIof the same discharge station. Thereafter, if the operator again selectsthe same station for another article carried by feed belt 10 behind thefirst article for which that station was selected, the consequentclosure of contact 41 will cause the second relay 4011 to operate sincecontact 40I-II is closed. In similar fashion, relay 4011 will lock inthrough its latching contact 40IIa and a normally closed contact 625: ofanother, related relay 62, and will also condition the primaryenergizing circuit of the next stacking relay of that station foroperation. Then, if the same station is again selected as the dischargepoint for another article before the first article selected therefor hasbeen discharged at that station, the third stacking relay will beenergized and latched in, thereby conditioning the next followingstacking relay for operation, and so on.

Each successive energized stacking relay 40 corresponds to a difi'erentarticle 11 selected for discharge at that Station. As described later,the discharging operation includes energizing of the related relay 62,thereby opening its contact 62a and thus deenergizing the relatedstacking relay. However, this will not deenergize any of the energizedfollowing stacking relays of that station, since they are held inthrough their latching circuits. Also, if the same station is then againselected for article discharge, this will result in energizing the firstrelay 40 (of that station) which stands unenergized. This is because, asset forth above, the primary energizing circuit of any stacking relayincludes a normally open contact of all preceding stacking relays ofthat station.

Stepping switches Referring to FIG. 4, there is provided for eachdischarge station a stepping switch 45. It will be recalled that eachdischarge selector button 14, when operated, will mechanically close itscontact 46 (FIG. 1a). Each contact 46 (FIG. 4) is connected to acorresponding one of the stepping switches 45 through respectivenormally closed contacts 33a of the previously described interlock relay33. Whenever any given selector button 14 is operated, it will cause therelated stepping switch 45 to advance one step. As further shown in FIG.4, each contact 46 is connected to all the stepping switches for thestations which lie upstream thereof. Therefore, operation of anydischarge selector button 14 will cause not only the associated steppingswitch 45 to advance one step, but will also advance all the precedingstepping switches one step. It will be understood that the diodes 47 areprovided merely for the purpose of preventing sneak circuits.

There are also provided for each stepping switch 45, i.e., for eachdischarge station, a number of additional stepping switches 50. There isone such stepping switch 50 for each of the stacking relays 40 of adischarge station. FIGS. 5 and 6 show the various stepping switchesassociated with one discharge station, the arrangement being the samefor all stations. The stepping switches 45 and 50 for any one dischargestation are interconnected in the manner shown in FIG. 6. That is tosay, the various contact points, ten for example, of the stepping switch45 are each respectively connected to the corresponding points of allthe stepping switches 50 for that discharge station. Each steppingswitch 50 itself is, as shown in FIG. 5, connected across the appliedpower potential through a re spective normally open contact 4% of arelated one of the stacking relays 40, a normally closed contact 53a ofa relay 53 (FIG. 6), and a normally closed interrupter contact 50a ofthe stepping switch itself. There is a separate relay 53 for eachstepping switch 50. Therefore, when any given stacking relay 4% isoperated as described earlier, the related stepping switch 50 willcontinue to step until its commutator arm 51 (FIG. 6) reaches the samestepped position at which the commutator arm 52 of stepping switch 45stands. This will complete the circuit for the relay 53, energizing thelatter whereby its normally closed contact 53a will open, breaking thecircuit for that stepping switch 50. It should be noted, however, thatthere is no electrical interconnection between commutator arms 50 and 51when they are in their home positions,

Briefly reviewing the discussion to this point, depression of any givendischarge selector button 14 by the operator will cause the followingcircuit conditioning functions to occur: the stepping switch 45 for theselected discharge station will advance or step up one step, as will allprevious (upstream) stepping switches 45; a given stacking relay 40 forthe station will operate; and the commutator arm of stepping switch 50corresponding to the one stacking relay 40, of the selected station,which is operated, will continue stepping until its commutator arm 51 isat the same position as the commutator arm 52 of stepping switch 45.

The operated relay 53 will lock itself in through its own normally opencontact 53b in series with an off normal contact 54 of stepping switch50. This latter contact is conventionally provided in commerciallyavailable stepping switches. It is normally open when the steppingswitch is at its home position, but is otherwise closed. Therefore,relay 53 once energized will remain energized until the commutator arm51 of stepping switch returns to home position.

The selection of a discharge station having been made as describedabove, the article 11 for which that selection was made is carried byconveyor belt 10 past each station photocell 21; and will beautomatically ejected at the selected station as follows. As the articlepasses each photocell 21, the momentary blockage of light falling onthat photocell causes a corresponding respective relay 60 (FIG. 7) to beenergized because of the rise in the photocells resistance. Operation ofrelay 60 will close its normally open contact 60a which is effective tostep all stepping switches 45 and of that station back one step. At thispoint, it should be mentioned that stepping switches 45 and 50 areprovided with both conventional step up and step down means. In theusual commercial form, such a stepping switch includes a first coileffective to operate a count-up pawl; and a second coil effective tooperate a count-down pawl. The contact a of relay 60 is in series withthe step-down coils of stepping switch 45 and stepping switches 50.Therefore, the switches will be stepped back one step each time anarticle 11 carried by the conveyor belt 10 passes the photocell 21 forthat station.

Each stepping switch 50 includes a second level having a commutator arm61 (FIG. 8). When, and only when, the stepping switch is in its homeposition, this second arm 61 will complete the circuit for a relatedrelay 62 through a normally open contact 530 of the previously mentionedrelay 53. It will be recalled that this latter relay is energized solong as the associated stepping switch 50 is at other than homeposition.

Operation of any one of the station relays 62 is effective to cause thedischarge of the article at that station, whose photocell 2 1 thearticle has just passed, by operating that stations discharge solenoid23, as follows. As seen in FIG. 8, respective normally open cont-acts62b of the various relays 62 for the given station are all arranged inparallel with one another and in series with the discharge solenoid 23for that station. It will be recalled that there is provided a separaterelay 62 for each stepping switch 50, and that there are as many of thelatter as there are stacking relays 40 for the given gate. Accordingly,it will be seen that operation of any one of the relays 62 will energizesolenoid 23 thereby swinging the related deflector arm 20 (FIG. '1) intothe path of the article 11 on the belt 10. The article 11 is thusdischarged from the belt at that station.

The foregoing system provides that each article 11 Will be automaticallydischarged at the station corresponding to the previously depressedselector button 14. A particular example will now be given. Assume thatthe system has at least five discharge stations; and that stations 5, 3,and 5 are selected, in that order, for three consecutive articles 11 onbelt 10 by operating appropriate ones of buttons 14. The first selectionsets up the following condition in the control circuitry for station 5:its stepping switch 45 advances one step from home position, as doswitches 45 for stations 1, 2, 3 and 4; while the first stepping switch50 (501) for station 5 also advances one step from home position.

The subsequent selection of station 3 advances stepping switches 45 forgates 3, 2, and 1 another step, so that these switches stand at twosteps from home, although switches 45 for stations 4 and 5 remain attheir one-step positions; and also advances the first stepping switch 50(501) for gate 3 one step from home.

The following repeated selection of gate 5 advances the steppingswitches 45 for all five stations an additional step. They, therefore,now stand advanced as follows: station 5-two steps; station 4-tw0 steps;stations 3, 2,

1three steps. This second selection of discharge station also causes thesecond stepping 50 (5011) of station 5 to move from home to the samestepped position as stepping switch 45, i.e., two steps.

The following events will take place as the various articles 11 forwhich the above selections were made are carried downstream past thephotocell 21 of each discharge station. It is important to recall heretwo things: (1) each article movement past a station photocell 21 stepsall the associated previously stepped stepping switches 45 and 50 ofthat station back one step; and (2) when any switch 50 at a stationsteps back into its home position, it causes discharge of the article atthat station.

The first article, destined for station 5, in passing each stationphotocell 21 will cause the stepping switches for the various stationsto step back one step to the following positions rfirom home: switches45 of stations 1, 2, 3two steps; switches 50 of stations 1, 2, 4nochange, since they have not previously been stepped from home position;switch 50I of station 3one step; switch 501 of station 5 to homeposition, thereby causing discharge of the article at thevstation, asselected, by operation of the associated relay 62 which causes operationof the station discharge solenoid 23.

The second article passing each station photocell 21 causes the steppingswitches to be stepped down to the following positions: switches 45 ofstations 1, 2, 3one step; switches 50 of stations 1, 2no change; firstswitch 50 of station 3ho-me position, thereby causing discharge of thearticle at that station, as selected.

The third article: switches 45 of stations 1, 2, 3to home position;switches 45 of stations 4, 5one step; switches 50 of stations 1, 2, 3,4no change; second switch 50 (5011) of station 5 to home, therebydischarging the article at the station, as selected.

Normalizing A separate, normally on, relay 63 is provided for eachdischarge station. As seen in FIG. 8, this relay is connected in serieswith a normally closed contact 620 of all the relays 62 of the station.In parallel with relay 63 are fixed resistance 64, variable resistance65 and a capacitor 66, to provide an adjustable slow release time forthe relay. When any one of relays 62 is operated as aforedescribed tooperate the discharge solenoid 23, opening of its contact 620 will breakthe circuit to relay 63 so that the [latter will start to release.Earlier, mention was made of relays 53 (FIG. 6), one of which wasenergized when the related stepping switch 50 stepped to the sameposition as stepping switch 45. Each relay 53 is provided with alatching circuit through off normal contact 54 of the associatedstepping switch 50, and also through contact 63a of relay 63. The factthat the stepping switch 50 has previously returned to home positionopened the contact 54. However, relay 53 up to this point has remainedlatched-in through an associated normally open contact 63a of normallyenergized relay 63. However, the .fact that relay 63 has now dropped outopens contact 63a, whereby relay 53 is deenergized. This will causecont-act 53c thereof to open, thereby deenergizing the one of relays 62which had caused the discharge solenoid 23 to operate through thecontact 62b. The latter contact will now open, deenerigizing solenoid23, thereby allowing the deflector arm 20 to return to its unoperatedposition under the bias of spring 27. The operated relay 62 having nowbeen deenergized, its normally closed contact 620 will now be closedreestablishing the energizing circuit for relay 63 whereby the latterreturns to its normal, operated condition.

If desired, means can be provided to normalize the stepping switches 45-and 50 to home position, under manual control, as follows. Referring toFIG. 4, a push botton resetting switch has a first normally open contact70a connected in series with all the stepping switches 45 throughrespective 01f normal contacts 71 of the various switches 45, and alsorespective interrupter contacts 72 of switches 45. Operation of contact70 will therefore complete the circuit for any stepping switch 45 whichis out of home position. The switch will step until it is at homeposition, at which time its oil normal contact 71 will open. Anothercontact 70b (FIG. 7) of the reset switch is provided for each station,connected to stepping switches 50 through an interrupter contact 73. Itwill be obvious from the foregoing description that at any one time twoor more of the articles 11 can be between successive discharge stations.

FIGS. 9 and 10 show another species of the system in which theprinciples of the invention can be embodied. In the system of FIGS. 1-8,all the articles 11 are placed on the conveyor belt 10 ahead of thefirst discharge station. In the species of FIGS. 9 and 10, however, thearticles can be loaded on conveyor 10 at various points betweendischarge stations.

Referring to FIG. 9, there are provided various sections S along thedirection of movement of belt 10'. Each sector includes one or moredischarge stations, and also is provided with a discharge selectionpanel 13'. Each selection panel 13 has selector push button 14' forselecting not only the discharge stations of that sector, but also thatdischarge stations of subsequent (downstream) stations.

Each discharge station of FIG. 9 is provided with discharge controlcircuitry as described previously in connection with FIGS. 1-8. Eachselector button 14' controls the stepping switches 45 of the sector S inwhich its control panel 13' lies in the same manner as aforedescribed.

In addition, however, any selector button 14' for selecting a stationlying in a subsequent sector controls further circuitry now to bedescribed. Each downstream sector S is provided with a a stepping switch(FIG. 10). The various stepped positions of the switch s commutator arm81 each correspond to a different discharge station within the sector.Respective contacts 82 each operated by a related button 14' of anyupstream sectors control panel 13' are connected to switch 80 of thedownstream sector containing the station corresponding to the button,through any suitable conventional control circuit 83, such as that usedto self-step a stepping switch to a desired position. The arrangement issuch that operation of a button 14 to select a station lyin in adownstream sector will step the latters sector switch 80 to its positioncorresponding to the selected discharge station within that sector.

The beginning of each sector S is marked by a light beam from a lightsource 84 falling on a photocell 85. An article moving from one sectorto another will interrupt the light beam, whereby photocell 85 willcause operation of a respective related relay 86 provided for eachsector. A normally open contact 86a of relay 86 is connected to thecommutator arm 81 of stepping switch 80. The various contact points ofthe latter are respectively connected to relays 90 each provided for adischarge station within the sector. A normally open contact 90a of eachrelay 90 is connected in parallel with the contact 41 (FIGS. 3, 10) ofeach related discharge station. It will be recalled that closure ofcontact 41 operates one of the stacking relays 40 for the selectedstation.

Another contact 90b, of each relay 90 is in parallel with the contact 46(FIGS. 4, 10) of each related discharge station. It will be recalledthat closure of contact 46 operates stepping switch 45.

Assume that an article has been placed on belt 10 in one sector and theselector button 14' (of that sectors control panel 13) for a dischargestation of the following sector is depressed. Operation of button 14'advances commutator arm 81 of stepping switch 80 of said followingsector to its contact point corresponding to the selected station, sothat the arm is now connected to the associated station relay 90. Then,as the article enters the next sector, which contains the selecteddischarge station, it will block the light falling on the sectorphotocell 85, operating relay 86 whereby its contact 86a now closes.This completes the circuit for the relay 90. Its contacts 90a and 90bclose, completing the circuits for stacking relays 40 and steppingswitches 45, which will thereupon operate as described earlier inconnection with FIGS. 1-8.

It will be seen from the foregoing that photocell 85 and stepping switch80 serve to delay operation of the stacking relays (and therefore ofstepping switches 50) and stepping switch 45 until the article hasentered the sector containing the discharge station selected for it.

For stacking purposes, each sector is provided with plural steppingswitches 80 controlled by related relays (not shown) in substantiallythe same manner as the stepping switches 50 and their stacking relays40.

The foregoing description sets forth in detail specific embodiments ofthe invention. It will be understood, however, that various changes canbe made in practice without departing from the broad principles of thein vention. For example, the selection means could be operatedautomatically as by sensing a punched card attached to each articleentering the system. The system of FIGS. 910 could be in the form of acompletely closed conveyor loop. Numerous other modifications can beeffected while still making use of the inventions principles.

Accordingly, it is intended the foregoing detailed disclosure beillustrative only and not in any way limitative of the following claims.

I claim:

1. In an article sorting system having a plurality of successive articledischarge stations; means for conveying articles successively to saidstations; and selectively operable discharging means at each station:one selection means for selecting any one of a number of said dischargestations; control means for effecting operation of a stationsdischarging means when an article is at the station selected for thatarticles discharge; said control means including means, responsive torepeated selection of the same given discharge station for differentgiven articles before the first of said given articles has beendischarged at said given station, for causing the discharge means ofsaid given station to operate only when said given articles are at saidgiven station; said control means comprising a plurality of controldevices for each discharge station, each of said control devices beingadjustable to a number of different conditions including adischarge-effecting condition; said control means further includingmeans, operable in response to operation of said selection means toselect a station for an articles discharge, for causing adjustment of atleast one of the control devices for that station before saidlast-mentioned article has arrived at the first of said plurality ofstations.

2. The combination according to claim 1, wherein each of said controldevices comprises a counting means.

3. The combination according to claim 2, wherein each counting meanscomprises a stepping switch.

4. The combination according to claim 1, wherein said control meanscomprises: a control element for each discharge station, with controlelement being adjustable to a number of different conditions; adjustingmeans responsive to the selection of a given discharge station foradjusting the control element for said station, and means connecting thecontrol devices for said station with the control element for saidstation in such manner that the adjustment of said control devices iscontrolled by the adjustment of said control element.

"5. The combination according to claim 4, wherein said adjusting means,in response to selection of a given discharge station, also effectsadjustment of the control elements for stations preceding the said givenstation.

6. The combination according to claim 5, wherein said connecting meanscauses one of said control devices to be adjusted to the same conditionas the related control element in response to operation of saidselection means to select the given station.

7. The combination according to claim 6, wherein the aforementionedadjustments of said control devices and control element are in onesense; and including means operable in response to the presence of anarticle at a discharge station for adjusting all adjusted controlelements of that station in the opposite sense.

8. The combination according to claim 5, wherein said control devicesand control element each comprises a step counter.

9. The combination according to claim 8, wherein said control devicesand control element each comprises a step counter.

10. In an article sorting system having a plurality of successivearticle discharge stations; means for conveying articles successively tosaid stations; and selectively operable discharging means at eachstation: selection means for selecting a discharge station; controlmeans for effecting operation of a stations discharging means when anarticle is at the station selected for that articles discharge; saidcontrol means including a control element for each discharge station,each control elemen-t being adjustable to a number of differentconditions; adjusting means, responsive to the selection of a givendischarge station, for adjusting the control element for that stationand for at least one preceding station.

11. The combination according to claim 10, further comprising means foreffecting an opposite adjustment of only the control element of a givenstation in response to movement of an article to said given station.

12. The combination according to claim 11 wherein each control elementcomprises a step counter.

13. The combination according to claim 10 wherein said system includesonly a single selection means for selecting all the discharge stationsof said system.

14. The combination according to claim 10 wherein said system includesplural selection means each for selecting at least some of saiddischarge stations starting with a different given upstream station.

15. The combination according to claim 7 wherein said system includesonly a single selection means for selecting all the discharge stationsof said system.

16. The combination according to claim 7 wherein said system includesplural selection means each for selecting at least some of saiddischarge stations starting with a different given upstream station.

17. The combination according to claim 1; further comprising not morethan a single sensing means provided for each separate discharge stationfor sensing the presence of an article at said discharge station tocontrol said control means; and wherein said control means is effectiveto cause discharge of articles at the respective discharge stationsselected therefor even though a number of articles are disposed on saidconveying means between two successive discharge stations.

18. In an article sorting system having a plurality of successivearticle discharge stations; means for conveying articles successively tosaid stations; and selectively operable discharging means at eachstation: one selection means for selecting any one of a number of saiddischarge stations; control means for effecting operation of a stationsdischarging means when an article is at the station selected for thatarticles discharge; said control means including means, responsive torepeated selection of the same given discharge station for differentgiven articles before the first of said .given articles has beendischarged at said given station, for causing the discharging means ofsaid given station to operate only when said given articles are at saidgiven station; said control means comprising a plurality of controldevices for each discharge station, each of said control devices beingadjustable to a number of diiferent conditions including adischarge-effecting condition; said control means further includingmeans, responsive to the aforementioned repeated selection of the same,given station by said selection means, for causing adjustment ofdiflerent respective ones of said control devices of said given station.

19. The combination according to claim 18, including means for sensingthe presence of an article at each discharge station.

20. The combination according to claim 19, wherein each said sensingmeans comprises a photocell and a source of radiant energy so arrangedthat the articles carried by said conveying means move therebetween.

21. The combination according to claim 19, wherein said control meansincludes means for changing the adjustment of at least some of saidcontrol devices for a station in response to the sensing of an articleat that station by said sensing means.

22. The combination according to claim 21, wherein the adjustment ofsaid control devices caused by said sensing means is opposite in sensefrom the adjustment caused by said selection means.

23. In an article sorting system having a plurality of successivearticle discharge stations; means for conveying articles successively tosaid stations; and selectively operable discharging means at eachstation: selection means for selecting a discharge station; controlmeans for etfecting operation of a stations discharging means when anarticle is at the station selected for that articles discharge; saidcontrol means including a control element for each discharge station,each control element being adjustable to a number of differentconditions; adjusting means, responsive to the selection of a givendischarge station, for adjusting the control element for that stationand for a plurality of preceding stations.

24. The combination according to claim 23; wherein said plurality ofpreceding stations comprises all the stations which precede said givendischarge station.

References Cited by the Examiner UNITED STATES PATENTS 3,075,653 1/1963Wales 214-11 3,084,784 5/1963 Zouibek 2l411 X 3,128,867 4/1964 Karcher21411 3,141,540 7/ 1964 Burkhardt 198-38 3,152,681 10/1964 Byrnes 19838MARVIN A. CHAMPION, Primary Examiner.

WILLIAM B. LA BORDE, GERALD M. FORLENZA,

' Examiners. M. TEMIN, 'Assistwnt Examiner.

1. IN AN ARTICLE SORTING SYSTEM HAVING A PLURALITY OF SUCCESSIVE ARTICLEDISCHARGE STATIONS; MEANS FOR CONVEYING ARTICLES SUCCESSIVELY TO SAIDSTATIONS; AND SELECTIVELY OPERABLE DISCHARGING MEANS AT EACH STATION;ONE SELECTION MEANS FOR SELECTING ANY ONE OF A NUMBER OF SAID DISCHARGESTATIONS; CONTROL MEANS FOR EFFECTING OPERATION OF A STATION''SDISCHARGING MEANS WHEN AN ARTICLE IS AT THE STATION SELECTED FOR THATARTICLE''S DISCHARGE; SAID CONTROL MEANS INCLUDING MEANS, RESPOSNIVE TOREPEATED SELECTION OF THE SAME GIVEN DISCHARGE STATION FOR DIFFERENTSELECTION ARTICLES BEFORE THE FIRST OF SAID GIVEN ARTICLES HAS BEENDISCHARGED AT SAID GIVEN STATION, FOR CAUSING THE DISCHARGE MEANS ONSAID GIVEN STATION TO OPERATE ONLY WHEN SAID GIVEN ARTICLES ARE AT SAIDGIVEN STATION; SAID CONTROL MEANS COMPRISING A PLURALITY OF CONTROLDEVICES FOR EACH DISCHARGE STATION, EACH OF SAID CONTROL DEVICES BEINGADJUSTABLE TO A NUMBER OF DIFFERENT CONDITIONS INCLUDING ADISCHARGE-EFFECTING CONDITION; SAID CONTROL MEANS FURTHER INCLUDINGMEANS, OPERABLE IN RESPONSER TO OPERATION OF SAID SELECTION MEANS TOSELECT A STATION FOR AN ARTICLE''S DISCHARGE, FOR CAUSING ADJUSTMENT OFAT LEAST ONE OF THE CONTROL DEVICES FOR THAT STATION BEFORE SAIDLAST-MEMTIONED ARTICLE HAS ARRIVED AT THE FIRST OF SAID PLURALITY OFSTATIONS.